Multifunctional T-cells (CD4+ and CD8+) have been implicated in both a protective (vaccine-induced and/or latent infections) as well as acute infection capacity during the immune response to various intracellular pathogens including Mycobacterium tuberculosis [64,65,66,67], Francisella tularensis [68], Salmonella typhimurium [69], Leishmania spp. The gene discussed is CD4; the disease is disease arising from reactivation of latent virus.